You can't download it on Steam yet, it's not on Steam yet, it won't be until it is released. When it is released you will find a Steam key in your account pages on the tgc site which you will then need to redeem on Steam.
Primary Desktop:
i7 7700,k NV1070 8GB, 16GB 3200mhz memory, 1x 2TB Hybrid, Win10.
Secondary Desktop:
i5 4760k, NV960 2GB, 16GB 2333mhz memory, 1x 2TB Hybrid, Win10.
Primary Laptop:
i5, NV1050 4GB, 8GB memory, 1x 1TB HDD, Win10.
Secondary Laptop:
i3, Intel 4000 series graphics, 6GB memory, 1x 500gb HDD, Win8.1.
